Ultrasound Biomicroscopy and Optical Interferometry Before and After Cataract Surgery
Purpose
To evaluate and predict the actual IOL position in comparison to effective lens position (ELP) by new quantitative analysis of the anterior segment using new landmarks. Lens and IOL position were analyzed in myopic and hyperopic patients before and after cataract surgery using ultrasound biomicroscopy (UBM) and Lenstar interferometry.
Methods
This is a retrospective non-randomized study comprising 46 eyes of 46 patients. Patients with UBM exams before and after cataract surgery included images of both ciliary bodies, scleral spurs, cornea and other anterior chamber structures. A new system of quantitative analysis of the anterior segment was developed using Lenstar and UBM to describe the anterior segment anatomy. Ciliary apeX depth (XD), scleral spuR depth (RD), peripheral IPE depth (ID) and corresponding horizontal distances apex-to-apex (XTX), spur-to-spur (RTR), IPE-to-IPE (ITI) were defined as new landmarks. Ciliary angle and iris angle define movement of ciliary-lens membrane (CLM) and iris membrane (IM).
Results
The Lenstar AC was 3.11 +/-0.51 mm, the IMM-AC was 3.22 +/-0.48 mm and the UBM-AC was 3.20 +/-0.50 mm with a correlation coefficients of 0.96 and 0.97 compared to Lenstar. Preoperative RD was 3.86 +/-0.27 mm, ID 4.18 +/-0.29 mm, XD 4.59 +/-0.4 mm. Postoperative RD was 3.80 +/-0.27 mm, ID 4.22 +/-0.28 mm, XD 4.76 +/-0.32 mm. Preoperative ciliary angle was -0.3 +/-12.2 mm, IA 9.7 +/-6.3 mm. Postoperative CA was -14.57 +/-12.86 mm, IA -0.77 +/- 2.34 mm. Other landmarks and distances are analyzed, as well as effect of dilation and size of anterior and posterior segment.
Conclusion
We have confirmed our previous findings that UBM is suitable for new quantitative analysis of the anterior segment based on good repeatability and correlation with Lenstar interferometry. New landmarks, such as scleral spur and peripheral IPE are useful as reference structures and to predict IOL position.